This is a variant of "catch you on the flip side" and refers to the B side of a vinyl record. It is generally used as a way of saying "I'll talk to you soon" or "I'll catch up with you later".
"Hey I'm heading out bro, but I'll catch ya on the Bside"
Simple... The Reverse Tit Fuck with the Ball Gobble. Rather than standing over her stomach while tit fucking, you stand over her face making it easy for her to gobble your balls at the same time.
"Your wife made me feel very welcome by offering me coffe, pie, and an R.T.F. with the B.G."